For many applications, the thermal coupling of relatively rigid energy generating and dissipating devices requires a resilient or compliable interface to increase the contact area, and thus the thermal coupling, between the devices. Materials used for such interfaces are commonly referred to as thermal interface materials (“TIMs”). Examples of TIMs are conductive greases, solders, etc. However, TIMs are usually in the form of thin films of a suitable polymer which may be loaded with particles of thermally conductive materials such as diamond or boron nitride. The structure for handling TIMs is usually a composite tape which includes a sheet such as a foil upon which the TIM is disposed, but sometimes includes no reinforcement. The tape also includes a bandoleer, which is typically a long strip of release film disposed over the TIM for ease of handling and for protecting the TIM. To use the tape, the bandoleer is removed and the TIM is adhered to the dissipating device. To complete the thermal coupling between the devices, the energy generating device is forced into contact with the foil.
The prior art discloses heat sinks and electrical components pre-coated with a layer of a material such as thermal grease. This art recognizes that contamination and migration of the thermal grease is substantially reduced by covering the coated areas with a release liner that is removed prior to the assembly of the heat sink into a circuit board or other assembly. By providing a pre-coated heat sink, productivity can be enhanced, by increasing accuracy with which the thermal grease is applied, thus eliminating waste and clean up. Areas of the heat sink can be either fully coated, or portions selectively coated, and the coating may be accomplished by a silk screening or pad printing process, which includes using an applicator head. The release liner is preferably provided with a pull-off tab to facilitate the removal of the release liner.
Delivery systems for TIM (thermal interface material) may include untabbed, automated dispensing systems or pick-and-place systems. Others may be untabbed, die-cut parts on large sheets or in roll form, these are “picked off” the carrier liner.
Many TIMs are provided in a continuous roll form with tabs for easy removal of the part from the carrier bandoleer/liner. A person would unwind the roll to the next part, grip the tab and peel the tab and the part (TIM) from the bandoleer. The part would be applied to the interface (heat sink) and then the tab would be removed from the part (TIM). If the tab is needed as a protective liner for the TIM, it would be left in place until the component heat sink is ready for final assembly into the PC. In this case the liner or a portion of it generally has a distinctive color to alert the assembler to remove it prior to final assembly.
One of the main problems with the TIMs disclosed in the prior art is the ability to manipulate or handle the associated tape after removal from the bandoleer. Also lifting of the TIM from the heat sink occurs when removing the tab tape. Thus, it would be desirable to provide an improved tape structure which improves the ability to manipulate or handle a film or sheet upon which a TIM has been disposed and is exposed for purposes of contacting to an associated device.
The teachings hereinbelow extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above-mentioned needs.